In the prior art, this kind of device is described in, for example, Japanese Patent Laid-Open No. 54-57759. In this invention, a transport path is formed between an outer guide plate and an inner guide plate in the traveling direction of a sheet of paper. The transport path is inverted and the direction is changed by 90° relative to the traveling direction of the sheet, so that the sheet passing through the transport path between the outer guide plate and the inner guide plate is inverted by 180° and the direction is changed by 90°.
In Japanese Patent Laid-Open No. 63-134437, a sheet of paper is inverted at a point of a loop transport path around an axis along a transport direction.
In Japanese Patent Laid-Open No. 2000-135851, an intermediate transport path is provided like conveyer belts which are a plurality of belts looped over a pair of rollers. On the intermediate transport paths, an inverting/refeeding roller is disposed so as to have an axial direction at 45° relative to a transport direction, a plurality of auxiliary rollers pressed in contact with the inverting/refeeding roller are provided, and inverting guides disposed close to the outer surface of the inverting/refeeding roller with a small gap are provided between the auxiliary rollers.
Further, a sheet of paper is transported on the intermediate transport path while being sucked by a suction fan. The sheet introduced between the inverting/refeeding roller and the auxiliary rollers is guided by the inverting guide so as to be turned along the outer surface of the inverting/refeeding roller, so that the traveling direction of the sheet is changed by 90°.
In Japanese Patent Laid-Open No. 5-278894, an endless transport belt having a plurality of holes is looped over a pair of rollers, the transport belt is rotated by the driving of the rollers, a sheet of paper is sucked by a first sucking device which sucks air from the outer surface of the transport belt through the holes provided on the transport belt, and air is sucked from the outer surface of the transport belt through the holes of the transport belt by a second sucking device provided upstream from the first sucking device in a paper transport direction.
In Japanese Patent Laid-Open No. 2001-18512, the size and grammage of paper are detected by a paper size detector and a paper grammage detector, an ambient temperature and an ambient humidity are detected by a temperature/humidity detector, and the driving force of a motor for a fan is controlled by a control unit such that based on paper information having been detected by the paper size detector and the paper grammage detector, a proper paper suction force is obtained in consideration of the temperature and humidity having been detected by the temperature/humidity detector.
In Japanese Patent Laid-Open No. 1-104560, a device is provided for changing the suction force of a suction device according to the kind of paper in a transport device including the suction device.